


The World Killers

by KarryBeta, KarryMaster



Series: Twin Earth [3]
Category: Supergirl (TV 2015), The Flash (TV 2014)
Genre: F/M, KaraMel, Monara, Multiverse, Snowallen, Superflash - Freeform, The Millma Verse, Tumblr: snowbarryweek, twin, world killers - Freeform
Language: English
Status: Completed
Published: 2018-09-20
Updated: 2018-09-20
Packaged: 2019-07-14 14:29:52
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 7,199
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/16042358
Author URL: https://archiveofourown.org/users/KarryBeta/pseuds/KarryBeta, https://archiveofourown.org/users/KarryMaster/pseuds/KarryMaster
Summary: When two Earths decide to hop to the same world, they get there just in time to help save the entire world.





	The World Killers

**Author's Note:**

> Note 1: This is the crossover between three Earths (which coincidentally were all Karry Master's Earths) chosen by our Facebookers. Hope you enjoy.
> 
> Note 2: For both SnowAllen and Twin, this takes place after the Darkseid battle in Karry Universe. It also takes place after Prime and Mutant got SnowAllen Cisco back (to be covered in the next lot of Prime chapters).
> 
> Facebook; Fanfiction Millma Verse Page

-SnowAllen Earth-

Cisco sat in the Warehouse, wearing the goggles that Prime and Mutant Cisco's made keeping him sane – the only way he could control his power now was wearing the goggles all the time, without them he would lose it. The other Ciscos had tried other means, but as yet couldn't; the goggles were the only option and Cisco would never be able to take them off; Barry had offered to look into more comfortable options than wearing the goggles all the time, however.

However, he felt out of place. Harrison Wells, Jesse, Belle, Barry, and Caitlin had a smooth dynamic going in the years since he had been in the asylum, having alliances with Sara in Starling and with the multiverse – it was like he was not needed here.

"Cisco?" Caitlin said, making him look up. "It's time to test your power."

"I don't know," Cisco said; even with the goggles he was afraid to use them, afraid of losing himself once more. The group had let him get used to normal life again, but now they were trying to get him to experiment with his gifts.

"Ignoring your gifts is never the answer," Barry appeared. "Those goggles only lessen the powers to a point where you can control them – it does not suppress them completely. You need to learn to use them, to keep control, even with the goggles. Which is why opening a portal to another world is a good test run."

Cisco was relieved at least Barry was the same. Still as unsocial and unaware of people's feelings as ever. Caitlin though put a hand on his shoulder for comfort. "Me and Barry will be right with you," Caitlin assured him.

"And we have a whole system of worlds to choose from," Jesse stated. "Someone, choose a number."

"How about a perfect 10?" Caitlin said with a smirk.

"Earth 10 also known as SuperFlash Earth," Jesse said, at the computer. "Six years ahead of us in time. According to the system, no real problems there. Seems like the perfect quiet Earth to go to."

"Cisco?" Barry said, and Cisco moved over to Jesse to looked at the information in the system. Nodding, he went to open a portal – his portals were not as wild as the one his alternates made; they were rounder, and you could see what you were stepping into. In this case, they could see just an average city street.

-Twin Earth-

In the L-Corp warehouse, Cisco, Winn, Caitlin, Kara, Kayla, Barry, Mon, and Grodd were there with their newest member: Cisco's twin sister, Cesca. They had recruited her into the team after realizing she had the same powers as Cisco counterparts after the explosion in STAR Labs. Cisco and Winn had managed to make her the same goggles as Cisco counterparts, with some help from Cesca herself – since she reminded the boys she was just as smart as them.

"Okay, time to test out your world hopping sister," Cisco said, turning to Cesca.

"So, you just want me to open a portal to another world?" Cesca frowned. She had been seeing into other worlds fine, but she was nervous. She'd never done this before. "What if… something goes wrong?"

"That's why myself, Kayla, Barry, and Mon are going," Kara reassured Cesca. It was originally just going to be her and Mon, but Kayla and Barry had been around and while the two still refused to be everyday heroes, they were helpful and agreed to come anyway. Barry himself was wearing his NASCAR outfit he used, with matching red helmet.

 _Grodd come with mommies,_ Grodd thought.

Both Kayla and Kara gave a smirk at the same time at this. "Okay, Grodd comes too," Kayla said. "See nothing to worry about."

"Except us leading an invasion with so many of us," Cesca tried to joke as Kara frowned at this.

"So, someone pick a number," Winn said, ignoring Cesca's comment, he by the computer.

"How about a perfect ten?" Caitlin offered.

"Oh, Earth ten," Winn said, bringing up information about the Earth on the computer. "Also known as SuperFlash Earth. We can assume like most of the multiverse, Kara and Barry are together." Barry put an arm around Kayla, easily able to tell who Kayla was, as Kara was in her outfit and Kayla just had on her normal red leather jacket with the House of El symbol on it. "Six years ahead of us in time. Seems like a nice Earth."

"Cesca?" Cisco said and Cesca looked at the computer, taking in the information.

Nodding she put on her goggles and held out her hand. At first nothing happened, but she persisted as a blue ripple extended from her fingers, expanding quickly enough for a person to step through. The group looked at each other before Kara stepped forward first, followed by Kayla, Barry, Mon, and Grodd. Cesca took a breath and stepped through her own portal…

-SuperFlash Earth-

On the empty street two portals opened practically side by side; one was a perfect circle, able to see through to a warehouse on the other end, while the other was wild and blue, that was until the five people and one gorilla came out. From the round portal, at the same moment, a Barry, Caitlin, and Cisco stepped out, both portals closing, leaving the groups looking at each other in shock.

"Did you just come here?" Kara asked as the other group eyes' seemed to go to Grodd. "It's fine. He's good."

"Yes, I remember you from Karry Universe. You're the one with the good Grodd. Twin World, right?" Caitlin asked, remembering the event when they'd all gone over to help with some Dark alien.

"Yeah," Kara said, seeming to be taking the lead. "And your?"

"SnowAllen," Caitlin said. "Me and Barry are together." She explained the name as her Barry put an arm around her. Twin Barry made a face at that, as he once again took his wife's hand; Kayla smiled at that. SnowAllen Barry gave Twin Barry a look at that, still not understanding why his counterparts did not seem to want to be with Caitlin. "What are you doing here?"

"Testing out Cisco's power," SnowAllen Caitlin continued. "We chose this Earth as it was the perfect 10."

"Really? That's what we did!" Cesca spoke up. "Perfect 10."

"Huh. It seems we just did the exact same thing at the exact same time," Mon voiced out loud. "What's the chances of that?"

"Actually…" SnowAllen Barry started, "considering the similar people and personalities and the similar circumstances the probability of any two Earths doing a similar or the same events at the same time is pretty high. I could do the math if…"

"Barry," Caitlin said, interrupting her husband and noticing the looks he was getting from the Twin World people. "The question was rhetorical. They didn't actually want an answer."

"Oh," SnowAllen Barry said. Rhetorical questions always got him. When he asked a question he always wanted an answer.

"Guys," Cesca said drawing attention to her. "Why is there no one but us on this street?" The group finally looked around. They were in National City, on a perfectly normal block, except that they were the only ones on it. No people. No cars on the road. The city did look more advance then normal, but the group had just thought that was because they were six years ahead.

That was when a loud noise and sounds of explosions hit their ears. "I think that answers that question," Kara said as Grodd instantly jumped up to climb the building.

 _Big fight,_ Grodd thought. He was wearing his super-shirt.  _Another mommy and speedy daddy fighting three women. Mommies, should Grodd help?_

"Yes Grodd, help!" Kara yelled out and Grodd went charging towards the battle, leaping across buildings. "You heard me. We help." Kara flew up right away and Mon jumped up to the top of the building Grodd had just climbed.

"Go," Caitlin told her Barry and SnowAllen Barry put his mask up and ran off. Caitlin used her own powers to summon plants to follow on them.

"What about you two?" Cisco asked Kayla and Barry who looked at each other.

"Come on," Kayla sighed to her Barry, wanting to make sure her sister and gorilla were safe anyway. "You two, stay." Kayla was pointing at Cisco and Cesca as she said it.

"We're getting way too use to this hero thing," Twin Barry said putting his helmet on and running up as Kayla flew up.

…

SuperFlash Barry and Kara were fighting three women – all of them dressed in black; the leader was a white woman wearing a mask who had the same powers as Kara, then a black woman who could fly and had a supersonic scream, and the last was an Asian woman with yellow eyes and long nails.

They were shocked when the gorilla in a super-shirt joined them, ploughing into the three villainous women. "Is that Grodd?" Barry asked out loud, confused.

"Oh, a big monkey," the woman with the long nails said, she was flying like the other two and only just avoided the attack by the Gorilla, but now came closer to him.

"He's not a monkey," Twin Kara's voice called before Grodd could, and she used her heat vision on the woman's nails, figuring they were the dangerous part of this woman. SuperFlash Kara and Barry didn't have time to take this in as the other two women rejoined the fighting as they noticed others joining in – a Mon-El, another Kara, a Caitlin controlling plants and another Barry.

Finally, another Barry showed; only he was wearing a helmet and different outfit. Kayla landing next to her sister. "And he's ours," Kayla finally said, smirking as Grodd pounded his chest, ready to attack when his mommies said.

"Then you will die as well," the woman not in battle with SuperFlash Barry and Kara said, her nails growing longer, a glint in her eye. "For you cannot destroy Pestilence! My virus will burn through the Earth. Killing all. Everyone who deserves it. Everyone will suffer."

"We can destroy you," Kayla said looking around, as her Kara kept an eye on Pestilence. Everyone else had joined in the fight with the other two, and even with the giant team up the two powerful women were easily overpowering the group, so she had to assume this one was just as powerful. Sharing this thought with her Kara, the twins agreed. "We can kill you unless you back down now." They had to give her a chance.

Pestilence laughed, obviously finding this offer ridiculous. "You cannot even touch me!" Pestilence called.

"Don't say we didn't warn you," Kara said, holding out her hand and Kayla took it. Both knowing they had no choice here. As Pestilence moved forward, from their combined hands came a large blast, hitting right into Pestilence. Pestilence seemed to try to go through it, fighting the blast, but the two could see it was hurting.

 _Stronger,_ Kayla thought back and the two put everything into it; the blast getting more powerful and finally going right through Pestilence. The two stopped when they saw the body falling, and both dropped to their knees on the ground below. Grodd leaped to them, picking up both his mommies for protection and ready to run them to safety if needed.

Unnoticed by Kayla and Kara, or Grodd, when Pestilence's body fell, her two comrades cried out, as if killing Pestilence physically hurt them. Both though shot up into the air and flew off – fast.

"You killed Pestilence," SuperFlash Kara panted, coming up to see the body dead, and looking her over.

"Is that a bad thing?" Kayla asked, still weak as she put her head on Grodd's shoulder. He was soft.

"No," SuperFlash Barry said, going to pick up the body. "No. This is a very good thing."

"Get that to the DEO right now," SuperFlash Kara told her husband who ran off. SuperFlash Kara turned to their visitors, all now lining up near Grodd; including the Cisco and Cesca left behind out of the battle. Mon, and the Barry with the helmet on, went to check on the twins in Grodd's arm. "What do we owe this visit to?"

"We both decided to test our world hoppers at the same time and choose this Earth," Mon said. "Don't ask him what the chances of that are." Mon added, pointing at the SnowAllen Barry.

"Well, good timing," SuperFlash Kara said. "You can follow me to the DEO."

….

SuperFlash Kara ran into the DEO with the world hoppers behind. Grodd was able to get through the door with both Twin Kara and Kayla in his arms.

"Pestilence," an Alex addressed her sister, Barry waiting for them with Pestilence's body now in a medical bay.

"You got the DNA. Can you make the cure?" Kara asked her sister.

"We don't have to," Alex said.

"What do you mean you don't have to? Clark…"

"Is fine," a voice said and SuperFlash Kara grinned at her cousin, who appeared in the medical bay doorway.

For the World Hoppers though, this Superman wasn't quite right – he had a similar look to the man Twin was used to, but not completely the same. This must be their Clark Kent. SuperFlash Kara hugged him.

"What happened?" SuperFlash Kara asked.

"It seems the virus was connected to Pestilence's life," a voice said and both Twin Kara and Kayla recognized it in shock.

 _No way!_ Kayla thought to her sister as Zor-El walked into the room with Alura by his side. There was a small boy with them as well, who ran to SuperFlash Kara while Alura was holding a little girl, no older than one – likely this Earth's Kara and Barry kids, although why the children were in the DEO was anyone's guess. SuperFlash Barry wasn't far behind the group, too.

"When Pestilence was killed the virus was killed with her," Zor explained.

"Everyone all over the cities is waking up healthy." Alex said, her eyes turning to the world hoppers. Kayla and Kara had asked Grodd to put them down, which he did, but seemed to be worried. "We are in your debt, it seems. You just saved thousands of people."

The two were not looking to her though; both were looking at Zor and Alura. "Mom?" Twin Kara finally said as Kayla stated: "Dad?"

"You're from another Earth," Alura said, kindly. "Kara has told us of the multiverse."

"But… how?" The two asked together.

"And who exactly were those women?" Caitlin added, interrupting the group. She, her Barry, and Cisco had been standing, back listening.

"World Killers," Zor said solemnly, resolutely, but SuperFlash Kara put a hand on her father's shoulder.

"You two clearly need solar lights," Alura said to Kayla and Twin Kara. "How about we bring you all to the medical area? Get the lights set up and explain."

"The monkey will have to stay here," Alex said. The main room was more than big enough for Grodd but the medical area had lower ceilings and was more confined.

 _Grodd, a gorilla,_ Grodd thought, showing his teeth.

"He does not like being called a monkey," Mon said playfully, helping Kara as Barry put an arm around Kayla. "And do not show him a banana…" They followed into the medical area though, where the solar lights were already set up for Kara and Kayla. The twins went under it together – taking out Pestilence had completely drained them.

"So…?" Caitlin said, again.

"World Killers are a Kryptonian experiment," Zor said. "A project I was a part of. We had fought off a Harvester invasion but it had been hard. We wanted to find a way to make powerful soldiers should the attack happen again. We needed warriors who were strong, powerful and with super-Kryptonian powers." He used the term super-Kryptonian in the same way they would 'super-human', as they were Kryptonians, after all.

"You were looking to make meta humans," SnowAllen Barry said. "Or, well in your case meta Kryptonians…. We don't have Kryptonians, or aliens, on our Earth really. You know we never did do experiments on mutating normal human DNA. Caitlin we…" SnowAllen Barry had gotten into his science mood, which Caitlin noticed made some people frown at him. Her Barry did tend to go into a tangent at times and this was not the time for him to get lost in his own little world.

"What's wrong with you?" Twin Barry asked, making his SnowAllen counterpart shut up and frown. "Please, continue." Twin Barry could see Kayla and Kara wanted an explanation.

"We went a step further then metas. So that they did not have their powers all the time, we thought of using a function used in some moles – they would be completely normal until the powers were needed and their bodies would transform completely. Unfortunately, with the transformation, also came deadly personalities. Wild, dangerous… killers. There was no way to control them. We were ordered to execute them, a failed experiment, but it was hard because… well one of them was made with mine and Alura's DNA." Alura took Zor's hand as he said this. "The one you saw today. The leader. Reign."

"She's our daughter," Alura said, hugging the baby she was still holding. The baby who must have been one in age and did not know the emotions just laughed. SuperFlash Kara whispered something in her son's ear and the boy went to hug Alura. Alura seemed to smile at the action.

"They were clearly not all destroyed," Cesca and Cisco said at the same time. Cisco looking at her, curious.

"Who are you?" Cisco asked. She was the Twin group world hopper Cisco knew, but hadn't gotten a name.

"Cesca," Cesca said. "We're twins… on my Earth, at least." Cisco stared at Cesca for a moment in surprise before turning back.

"A cult got hold of Reign, Purity, and Pestilence," Zor said, continuing his story. "They were the youngest of the World Killers… just babies at the time. It wasn't long before the destruction of Krypton so we… we had other things to worry about. The Kandor project. Getting Kandor safely away."

"I'm sorry, what?" Twin Kara asked.

"Years before Krypton's destruction a being tried to take Kandor city. We managed to stop him, but the device was still in place. We choose to use that device to shrink Kandor, to save a part of Krypton. It wasn't 100% effective though, which is why Alura and I sent Kara away separately," he looked to his Kara at this, but there was no regret in her eyes, even if there was in his. "There was a problem though: As we were putting Kara in her pod I got a call I was needed; I told Alura to stay but she wanted to be with me. We left our daughter and went to activate the device. We thought we would not be inside, but we were. The device… we were stuck in a time loop – the last minute of Krypton, until Kara and Barry found us."

"About a year ago, not long after this system was put in we received the shrunken city from an alien and discovered what it was. With our little genius here," SuperFlash Barry said, rubbing his son's hair, Damien laughing at his father antics, "we unshrunk the city of Kandor – found a nice place for it in the Nevada desert, in fact."

"Never expected to find my parents within," SuperFlash Kara said with a smile.

Twin Kara and Kayla looked stunned at all this; Mon and Barry put their arms around their respective girlfriends. "So you have a whole city full of powerful Kryptonians?" Kayla asked.

"Oh no," a man in the room said. Alex had went to stand by him and he had put an arm around her now. Kayla and Twin Kara were now so used to seeing Alex with Dinah they had to take a moment to process seeing her with a man. "The shrinking and unshrinking of Kandor radiated our cells; we can't take in the solar radiation like Kara or Kal."

"You're a Kryptonian?" Twin Kara asked.

"Dex-Em, from the House of Em," he said, seeming proud of it, and that was when the two noticed the symbol on his chest; remembering the symbol of the House of Em. It was encased like all Kryptonian symbols in a diamond-like border but was completely different to the familiar 'El' symbol, this involving various swooping lines and a few circles. "I requested to work in the DEO. My family has been Military Guild for a long time. I was in the Military Guild myself so it felt only right to protect my new planet the same way I would have Krypton."

"Can we go back to the World Killers?" SnowAllen Barry asked. He finding what Zor did to be amazing and wanted a word with him. It was rare for Barry to find someone as brilliant as him – Caitlin was the only exception he could think of.

"Yes, they were living human lives here on Earth, but something activated Pestilence and Purity. We don't even know who their human identities were. They gave completely over to the new one by the time we were able to confront them," Zor said.

"But Reign... Sam… she was my friend." SuperFlash Kara spoke. "When Purity and Pestilence came for her, she fought the transformation but… well… she failed," She had not known Sam was technically her sister until it was too late. "But she's still inside, in her head, and with Pestilence now dead the hold should be weaker."

"Pestilence and Purity were made to be a trinity, with their leader being Reign," Zor said. "One dead will weaken the whole – and I think I can save Sam. I was looking into ways to remove their powers, to keep the good identity and destroy the other before Krypton's destruction, but with impending death coming… I never got to finish. I think I found it though; I just need more time and some help."

"I can help," SnowAllen Barry said instantly. "I got my PhD in record time. I am considered the expert on meta human…"

"My husband is very smart," Caitlin cut off for Barry. "He would be of use."

"Why does no one let me finish here?" SnowAllen Barry frowned again.

"Well, I'll take all the help I can get," Zor said, putting a hand on SnowAllen Barry's shoulder. "But that's not all we need. We need to get Purity away from Reign."

"We can't do it again," Twin Kara and Kayla said together, shaking their heads. Even with the solar lights on them, it would be days before they could combine their powers like that again.

"We don't need you to," SuperFlash Kara said. "With Pestilence dead and her virus gone, it's not as major to kill them. If we can capture Purity and then free Sam of Reign then Purity would be on her own. We could maybe find her human identity. But we need a physic to free Sam. Alex, any word from J'onn on New Mars?"

"No," Alex said, shaking her head. "The new Martian colony…"

"You don't need J'onn J'onnz," Twin Kara and Kayla said together. "We've got your physic."

"Grodd!" SuperFlash Barry said, realizing who the two meant. "Will he…?"

"For his mommies and daddies, yes he will," Twin Kara said. "Grodd is a hero. Mon, just tell him what to do."

"Okay, so me, Mon, and Grodd will work getting Sam back," SuperFlash Kara said, determined now.

"I'll see about capturing Purity," SuperFlash Barry added.

"I'll join," Caitlin said, making SuperFlash Barry turn to her. Caitlin smirked as plants started to grow around Barry as if the floor he was standing on was suddenly soil. "In my experience, not too many people like messing with Mother Nature."

"As long as you don't bring the city down," her Cisco mumbled.

"Could use one more," SuperFash Barry said, looking around. "Where did Clark go?" He turned to his Kara at this who looked around too – Clark Kent was no longer in the room. SuperFlash Kara shrugged as then Superflash Barry's eyes went to Twin Barry, who had not said anything so far. Twin Barry seemed to notice the eyes on him.

"I'm not a hero," Twin Barry stated holding up a hand, knowing what his counterpart wanted.

"You agreed to help with major things," Twin Kara pointed out to Barry. "You jumped in before to help."

"On our Earth," Twin Barry pointed out. "And I went before to keep Kayla safe."

"You take Grodd to Reign and I'll go after Purity," Mon said, rolling his eyes, used to his Barry's non-caring attitude. Kayla gave Twin Barry a kiss though, and whispered something in his ear.

Twin Barry gave a nod. "Fine, I'll be there with Grodd. To tell him what to do," Twin Barry said.

"Seems we have a game plan," Alex said. "Now go. Zor, I'll send Winn to help you as well." Zor nodded as he put a hand on SnowAllen Barry's shoulder again, leading him away. Damien Allen followed his grandfather as well – the little six-year-old having a meta human ability that made him a genius.

Twin Barry kissed Kayla before heading towards where Grodd was, following by SuperFlash Kara. Mon gave his Kara a kiss before standing up.

"Come on," SuperFlash Barry said. "I'll show you two the armory. See if there's any gadgets you want." The three walked away at that.

 _Guess we'll just recharge,_ Kayla thought to Kara, who smirked as they laid back. The two were feeling better already.

…

SuperFlash Barry had brought the two world hoppers to the armory. Caitlin was looking at a pair of glasses that apparently enhanced eyesight and gave the wearer information on their surroundings. Mon, on the other hand, was testing out a sword, seeming to like it.

"A Mon came here to set up that system," SuperFlash Barry said. "And he liked this." Barry took out a small device which expanded into a shield. "It deflects attacks as well."

"Nice," Mon said, taking the shield and playing with the sword; at a certain position a beam of energy shot out of the sword and Barry grabbed another shield fast to stop it from hitting into another weapon.

"Yeah… I should have warned you that sword sends out a laser beam. Feel free to use it," Barry said, tossing a belt at Mon. "You can put it in that." Mon put the belt around his waist and put the sword in it; it seeming to disappear with only the hilt staying visible. "We're six years ahead of you guys and now have Krypton." Barry explained to the look on Mon's face. "Oh, ear plugs. They worked against Purity at first but when all three got together it wasn't enough, but now with Pestilence dead they could help again." Barry took the ear plugs giving them to the pair before turning to Mon. "By the way, what's up with your Barry?"

Caitlin looked up at that too, curious to find out why Twin Barry wasn't committed to the hero game. Mon shrugged, however. "He's just not into the hero thing," Mon said simply.

"Did his mom not die?" SuperFlash Barry asked; it was the only reason he could think of on why his alternate would not care about being a hero, if she hadn't.

"She did," Mon said. "It's how he got his powers – he got hit by a stray lightning bolt from the attack and in a coma for nine months. Woke up with powers and no memory of his life. His twin sister Bailey wanted him to be a hero, to find the man in the lightning and get their mom's killer, but Barry didn't want to. Didn't know or care about the woman he didn't know."

"Is there a Particle Accelerator on your Earth?" SuperFlash Barry asked and could see Caitlin was thinking the same thing by the look she gave.

"Exploded," Mon said. "Destroyed the city. Made meta humans."

"Be careful of Harrison Wells. Don't believe his paralysis," SuperFlash Barry warned.

"Or Tess Morgan," Caitlin chimed, in making SuperFlash Barry look at her. "That's the way it was on my Earth."

"Harrison Wells is dead," Mon stated, cutting off the conversation. "His twin brother, Harold, took over the labs but he's not in a wheelchair. And who's Tess Morgan?"

SuperFlash Barry and Caitlin looked at each other, both not sure what to say to that. Was it possible the Reverse Flash had died in his own explosion? "Wait, exactly how many twins does your Earth have?" Caitlin asked. "The blonde aliens, Barry and Bailey, Harold Wells, and clearly Cisco and Cesca."

"Me too," Mon said. "A brother, Mik. He went back to Daxom with my parents though. And our Caitlin is part of triplets."

"There's a good reason your world is called twin," Caitlin said after a moment, nodding impressed.

"Hey," Alex interrupted them over the coms. "Reign and Purity are back in the city; seem to be taking revenge for their sister's death. Grodd, Kara, and the Barry with the helmet are ready to go."

"Is Zor ready?" SuperFlash Barry asking, putting his cowl up.

"They are working on it," Alex said as the three moved out.

….

Reign and Purity were causing destruction in the city and causing nearby people to run. They were holding hands, like Twins Kara and Kayla had, but a burst of light hit into their hands causing them to split.

"I like this!" Mon said, jumping up with the sword in his hand. Before either World Killer could retaliate plants grew up and around Purity, physically moving her away. Mon moved to go after her.

Before Reign could go for her sister SuperFlash Kara was between them, eyes lighting up. "Sam! I know you're in there!" Kara called.

"Oh, Sam is long gone," Reign replied, her voice echoing and almost robotic.

"I don't think so," Kara said as Twin Barry ran up to the top of the building, his helmet on. Grodd jumped up next to him and Kara flew right into Reign to bring her down to the building, crashing next to Twin Barry and Grodd. The two rolled around, fighting, until Reign got the upper hand.

"Now Grodd!" Twin Barry said, using his arm as a tornado to get Reign off Kara. It didn't seem to faze Reign at all.

 _Sam,_  Grodd said in her head. Reign laughed as she realized what was happening.

"You think this will do anything?" Reign said, going to punch Kara but glaring at the gorilla.

Grodd looked at Barry who nodded.  _Samantha Arias. Sam, fight. Fight against Reign. Look at her,_  Grodd continued as Reign was punching Kara but Reign's fist stopped, surprising the World Killer.  _Look at your friend. At your sister. Fight Reign. Come back to us. Come back to your family._ Grodd sent a mental image of Kara, Barry, their kids, and Alura and Zor to Reign.  _Fight for them. Fight for yourself._

"Kara…" Reign spoke, but her voice sounded different and her eyes were no longer red.

"I'm here," Kara said, standing up wiping the blood off her face. "Sam…"

"No!" Her eyes went red once more.

"Sam, fight her!" Kara said.

 _Fight!_  Grodd commanded again, sending it into her mind with all the power he could muster.

"I'm here. Come back," Kara said, seeing her eyes go back and forth, from red to normal blue. "Sam…"

"Get out of my head!" Sam yelled and then she dropped to her knees, now her eyes normal and tears coming to her eyes. "Kara, kill me. End it now."

"No, I'm going to save you," Kara said, putting an arm on Sam and looking to Barry.

"Now Cisco," Barry commented, knowing that SnowAllen's Cisco had been looking in, waiting for his moment. A perfect portal opened to the DEO and Barry grabbed Sam from Kara and headed through.

Kara sighed as the portal closed. She got up and glanced to Grodd before the pair moved off, going to help with Purity – they could see the battle going on nearby

…

Meanwhile SuperFlash Barry, Mon, and Caitlin were battling Purity. The ear plugs were helping with Purity sonic scream somewhat, but with Reign still powerful their connection made the plugs only partially effective. They could still hear the scream, and it hurt, but not as bad as it could have been. Mon had the sword in one hand and shield in the other, using the latter to also protect himself against the scream – the special material the sword was made of, along with its laser, and adding Mon enhanced strength made the weapon super-effective.

Caitlin was using her plants to try to hold Purity back while Barry was using his speed to try to get punches on her. Purity was using her screams to break apart the plants and to stop Mon from getting close.

"We will avenge our…" Purity stopped, her eyes going in the direction of where Reign was with Kara, Barry and Grodd on the rooftop. "No, Reign I need…" Before Purity could finish, the distraction let Mon hit her hard, causing her to fly backwards. Caitlin had vines circle Purity, bringing her down. Barry ran up and put the device he had around her neck.

Purity tried screaming out, but she couldn't – the device blocked her power. "Oh, shut up," Barry said. "With your sisters gone that will easily hold back your powers. No more power boost for you."

"May I?" Mon asked and Barry nodded. Mon hit Purity over the head with the shield, weakened without her sisters, she was knocked out.

Kara and Grodd came running over. "Nice work," Kara said and Barry noticed his wife was injured. "I'm good. We got Sam."

"I know," Barry said. "Reason why we got her." Barry went to kiss Kara and Caitlin had to turn her head. Mon giggled.

"You're with your Kara," Caitlin said. "Them kissing is not weird."

"I see Kayla and Barry kiss all the time," Mon commented with a shrug.

"I'm here," a new voice said and everyone turned around to see Clark flying up and landing. "I came back… and I'm too late, aren't I?" Clark noticed Purity knocked out with no sign of Reign.

"Where were you?" Kara asked, rounding on her cousin.

"I told you, I went to go tell Lois I was okay," Clark said.

"You didn't tell us anything!" Kara said; she had been concerned for her cousin.

"I didn't?" Clark questioned, and everyone shook their heads. "Oh, okay, my bad." Kara rolled her eyes but then started to laugh.

"We should get her into lock up before she wakes up," Kara said, nodding back to Purity. "Just in case." Kara trusted Winn and her father devices, but Purity had once broke out on them – that had been due to Reign though.

 _Grodd got her,_  Grodd said, taking the unconscious World Killers and jumping off the building, the group going to follow.

-SuperFlash Earth-

SuperFlash Kara ran into the lab; Sam was in some machine, a device on her head and the rest of the machine connected to different parts of her body. She was screaming out.

"Is she okay?" SuperFlash Kara asked, her father. SnowAllen Barry, Winn, and Damien were in the room, watching. Damien ran to his mom and leaned into her legs. Apparently, the screaming was too much for the little boy.

"In about an hour she will be free of Reign forever," Zor said. "The device on her head will keep Reign from taking control. The electros are eliminating the portions of her DNA that causes the change. Reign will be gone. It is a painful process, however."

"How did you figure it out?" SuperFlash Kara asked.

"Well, I got to tell you I like our Barry and his videogame thing. This Barry is a genius. He found the last clue we needed," Zor said.

"The transformation was similar to a meta human I have seen on my Earth. So, using that information I was able to…" Snowallen Barry started, but his Caitlin came in. She still had the vision-enhancing glasses on her.

"Sweetie, you did the smart thing. No need to explain," Caitlin said, kissing her Barry. "And Cisco wants to head home." SnowAllen Barry nodded. "Can I keep these?" Caitlin held up the glasses. She liked using them against Purity.

"Well, it's really Alex decision as Director around here, but I don't think she will mind," SuperFlash Kara said. "Go. And thank you for helping." The two nodded as SuperFlash Kara picked up her son and headed out of the room with her husband and the group.

Cisco was standing there with Cesca, playing with the goggles on his head. "Don't take those off," SnowAllen Barry warned.

"I know," Cisco complained as he opened up his perfectly round portal to the warehouse.

"Well, this was fun… I think," Caitlin said. "We're SnowAllen Earth. Come by sometimes."

"Oh yes I would love to further study alien powers and how they differ from meta humans as we don't seem to have any aliens..." SnowAllen Barry said before pausing, understanding that people didn't seem to like him going into details here, besides Zor when they had been working on how to cure Sam. He liked the man. Barry nodded and simply turned and left, without even a goodbye as the portal closed behind him.

"That Barry was odd," a voice said. Kayla and Twin Kara were walking out besides Alura, who had Hazel in her arms still. Grodd smiled seeing his mommies up and healthy, and Twin Barry and Mon went to their respective girlfriends.

"You two are looking better," SuperFlash Kara commented. "We have to thank you two."

"And Mon, keep the sword, belt, and shield," Barry said and Mon gave a smile. "If there's anything else we can do…?"

"Actually," Twin Kara said; the two had been talking about it in their minds – they weren't feeling one hundred percent yet, but good enough to walk around. "We want to see Kandor…" SuperFlash Kara gave a smile.

"We have a teleport pad," SuperFlash Kara said and moved off, heading the way of the teleport pad. "Mom?"

"Have fun," Alura said waving her hand, indicating she was not coming. "I'll wait for Zor." Her Kara nodded at that.

SuperFlash Kara, Twin Kara, Kayla, Mon, and Twin Barry all went to the teleport pad; the thing lighting up, and a second later they were in Kandor.

Twin Kara and Kayla's breath was taken away as they saw the sights the buildings, the people. Beyond the addition of a few new buildings, the place didn't look different, except for the yellow sun in the sky, instead of red. Even Mon was in shock at the place – as Prince of Daxam, he had seen Kandor before, but he had never thought he would see it again.

"Since when are their three daughters of the House of El?" A passerby asked, smiling, and Twin Kara and Kayla realized this woman had to be Kryptonian. She wore a house symbol that neither could place. They didn't know of all the families on Krypton, after all.

"They are from another Earth in the multiverse," SuperFlash Kara answered and the woman gave a nod. "Come." SuperFlash Kara acted as a tour guide that was unneeded. Kara and Kayla had been to Kandor as a kid, they remembered the roads, the places, the parks – all the sights. It was different under the yellow sun, but the same as well.

The group went for lunch in a little restaurant in the heart of the city before heading back to the DEO. When they got there, Zor and Winn were waiting with an exhausted-looking Sam.

"Reign is gone," Zor said proudly; Alura was not far off. SuperFlash Kara moved forward and hugged Sam.

"I just… All those lives," Sam said into the hug.

"It's not your fault," SuperFlash Kara said, pulling away but holding on to her sister still.

"Sam?" Alura said coming up. "Zor and I are technically your parents..." Sam nodded as if saying she knew. "We would like to be your parents. We would like to help you, get to know you." Sam and Alura looked at each other for a moment before Sam leaned into Alura, and Alura hugged her close.

The twin group looked at the scene for a bit before clearing their throats to interrupt.

"We're, erm, going to go," Twin Kara said. "Thanks for… well showing us a piece of home."

"Thanks for coming at the right time and saving everyone," SuperFlash Kara replied, with a smile.

"Cesca?" Twin Kara said and Cesca put on her goggles and opened the portal. The twin group went in, one by one with Cesca being the last one to go – the portal closing behind her.

"You know, I liked those two Earths," Barry commented. He had their daughter now as Damien was next to them.

"Me too," Kara commenteD with a smile but turned to her family. Now that her sister was saved it was time for some family bonding.

-Twin World-

The group came out of the portal and Grodd went to head to his sleeping spot. "You were gone a while!" Cisco commented. "We were about to call and see what's going on."

"They decided to help out," Cesca said, taking a seat. "But first world hop went good. I think…"

"Alex?" Kara said seeing her sister was there and smiling at her. "They have Kandor there, alive and well. Mom and dad are alive. I'm married to Barry and have two kids." Barry gave Kara a look as he put an arm around Kayla. "The world… was… perfect."

"Well besides, the world killers," Kayla joked.

"You have a lot to explain…" Alex mused.

"I'm putting SnowAllen and SuperFlash down as close friends," Cesca commented to her brother as Kara did start explaining to Alex, while Kayla and Barry moved off. Mon went to check on Grodd.

"All worlds are friends though," Cisco pointed out to his sister. She was new to this after all.

"When was the last time you guys looked at this system. They have an area where you can list the Earths your closest too. Just added. Sort of like a favorite list. You can see who other Earths put down too. Seems Prime, Karry, and Mutant are a trio. They have each other down as close. Also considering the amount of times they call each other and visit," Cesca said bringing up the list and all the accounts of Prime, Karry, and Mutant calls and visits that had been entered into the system. "Why can't we be like them with SnowAllen and SuperFlash."

"Toss Prime on as a close friend. Astra basically lives on both worlds anyway," Kara stated with a smile as Cesca went to add close friends.

**Author's Note:**

> Post Chapter Note 1: I hope you like this chapter. I know Twin and SuperFlash had more of a plot than SnowAllen, but three-way crossovers are trickier, and I had more thoughts for the other two than SnowAllen anyway.
> 
> Post Chapter Note 2: I know the world killers were from the TV Show. When we started to include them in the stories it was before the TV show made all their history known so now we have a history for them that is off from the shows, including Sam and Kara being sisters. Also I just did not want to give Pestilence's powers to the others. As for why Kandor was used instead of Argo, this was written before Argo came back and the history of Kandor is a repeat of Karry Universe history for Kandor with some slight changes. Although you might be seeing our take in Argo soon though
> 
> Please kudos or comment.
> 
> Karry Master OUT!


End file.
